This revision includes the following changes:
 - [1] the Purchase_Process class was updated to log a user's purchase in the database by its book ID, instead of the sale ID.
 - [2] app/index.php had its "Search" tile changed to "My Books".
 - [3] explore.css has been updated to properly style the new "My Books" tile on the plugin home page.
 - [4] explore.min.css includes the changes made to explore.css.
 - [5] main.css was updated to style a ul.book-list more generically. Instead of expecting the books within this list to all include links and then style accordingly, the styles no longer assumes the list items have a link inside of them, and thus allows it to properly style book lists which do not include links.
 - [6] main.min.css includes the changes made to main.css.
 - [7] welcome-icons.png was updated to remove the old search icon from the sprite, and replace it with a book for the new "My Books" tile on the plugin home page.
 - [8] global.php was updated to include jQuery 2.0.3.
 - [9] the Book class's quickView() method was updated to include the word "by" before authors' names.
 - [10] the Sell_Book_Display class had its main SQL query updated to impose an additional restriction on the data it retrieves. The book the user is editing may not longer have been sold.
 - [11] ajax/delete.php was added to process book delete requests from the user.
 - [12] ajax/restore.php was added to process book restore requests from the user.
 - [13] my-books/index.php was added to allow the user to edit and delete their own books, as well as view their purchase and earning history.
 - [14] my-books.js was added to control the client-side functionality of restoring and deleting books.
 - [15] my-books.min.js was added as the minified version of my-books.js.
 - [16] my-books.css was added to style the my-books/index.php page.
 - [17] my-books.min.css was added as the minified version of my-books.css.
 - [18] mr-smiley.png was added for the my-books.css stylesheet for use when the user has not sold or bought any books.
 - [19] the User class was added as the data-retrieval class for my-books/index.php.
 - [20] the Delete_Process class was added to carry out a user's book deletion request.
 - [21] the Restore_Process class was added to carry out a user's book restoration request.
Merge branch 'master' of https://github.com/ffiadmin/book-exchange